Longitudinal adjuster for a vehicle seat

ABSTRACT

In a longitudinal seat adjuster ( 3 ) for a vehicle seat, in particular a motor vehicle seat, with at least one seat rail assembly ( 5 ) including at least two seat rails ( 11   a,    12, 13   b ) that define an installation space ( 15 ) and are powered by a motor to be relocatable in relative position to one another, at least a first spindle ( 20 ) and a first spindle nut ( 21 ) are located within the installation space ( 15 ) and interact with one another, and the installation space ( 15 ) allows room for a second spindle ( 30 ) and a second spindle nut ( 31 ).

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to DE 10 2004 010 489.1, whichwas filed on Mar. 4, 2004, and is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a longitudinal adjuster for a vehicleseat and, more specifically, to a longitudinal adjuster including a seatrail assembly with elongate seat rails mounted for there being relativelongitudinal movement therebetween, with the seat rails cooperating withone another to define an installation space that contains a spindlewhich interacts with a spindle nut for causing the relative movementbetween the seat rails.

BACKGROUND OF THE INVENTION

In a longitudinal seat adjuster of the kind mentioned in the aboveTechnical Field section, the installation space in the seat railassembly substantially solely contains the single spindle, the singlespindle nut, and other gearbox parts. In view of avoiding structuraldamage, and the needed longitudinal locking force, the structuralcomponents are appropriately dimensioned in order to meet the variousload requirements.

BRIEF SUMMARY OF SOME ASPECTS OF THE INVENTION

In accordance with one aspect of the present invention, a longitudinaladjuster for a vehicle seat, in particular a motor vehicle seat, has atleast one seat rail assembly with elongate seat rails mounted for therebeing relative longitudinal movement therebetween, and the seat railscooperate with one another to define an installation space. Inaccordance with this aspect, the adjuster further includes at least afirst spindle and at least a first spindle nut that are within theinstallation space. The first spindle and the first spindle nut aremounted so that they are meshed with one another for there beingrelative rotation therebetween, and so that the relative rotationbetween them at least partially causes the relative longitudinalmovement between the seat rails. Further in accordance with this aspect,the installation space is configured in a predetermined manner to becapable of having a second spindle and a second spindle nut within theinstallation space and meshed together.

Due to the fact that the installation space provides space for a secondspindle and a second spindle nut, a modular seat rail assembly isprovided which can be adjusted to the required longitudinal lockingforce via selecting the number of spindles. In case of low loadrequirements, only one spindle is used. In case of higher loadrequirements, two spindles are used. The first spindle has the functionof longitudinal adjustment. The second spindle increases thelongitudinal locking force. That is, in accordance with one aspect ofthe present invention, the seat rails are designed for the use of onespindle as well as two spindles. In accordance with one aspect of thepresent invention, the use of one or two spindles does not have anyeffect on the interface/mounting points between the seat rail assemblyand the vehicle structure, and likewise it does not have any effect onthe interface/mounting points between the seat rail assembly and thevehicle seat structure. That is, in one example, the use of one or twospindles does not have any effect on the outside geometry and outsidedimensions of the seat rail assembly. Each vehicle seat can have two ofthe modular seat rail assemblies mounted thereto, with the modular seatrail assemblies respectively relegated to being proximate the oppositesides of the vehicle seat and being respectively adapted for theanticipated seat belt force. That is, and for example, the seat railassembly that is mounted to the same side of the seat as the seat beltbuckle can have two spindles and respectively associated spindle nuts,whereas the other seat rail assembly can have only one spindle andassociated spindle nut.

For a seat rail assembly with two spindles and spindle nuts, a singledrive (e.g., drive motor) can drive both of the spindles or spindlenuts. In view of such a common, at least approximately synchronousdrive, the second spindle can be placed parallel to the first spindleand is threaded in the opposite direction as compared to the firstspindle (i.e., the substantially simultaneous rotation of the first andsecond spindle nuts of the same seat rail assembly is in oppositerotational directions). In order for the spindle nuts of the same seatrail assembly to be driven, the seat rail assembly can be provided witha common drive consisting essentially of one worm. The worm engages inthe two associated spindle nuts (which can also be referred to as wormgears due to their outer teeth) when two spindle nuts are present. Theworm can be powered by a single motor which simultaneously powers theworms of both seat rail assemblies to thereby activate both seat railassemblies. For a seat rail assembly with the two spindles and the twospindle nuts, it is necessary to allow for clearance between the secondspindle nut, on the one hand, and the worm and/or the second spindle, onthe other hand, in order to run smoothly and for the purpose oftolerance compensation. Nonetheless, this clearance can be characterizedas being optional and thereby nonlimiting with respect to the scope ofthe present invention. As an alternative to driving the spindle nuts,the spindles could be driven with a common gear assembly.

In accordance with one aspect of the present invention, the seat railsof a seat rail assembly can be modularly selected from three differentgroups of seat rails, such as for adjusting the load-handlingcharacteristics with regard to seeking to avoid structural damage. Inthis regard, a seat rail (e.g., selected from a first group) canpartially encompass the next seat rail smaller in size (e.g., selectedfrom a second group) and be partially encompassed by the next seat railbigger in size (e.g., selected from a third group). Although threegroups are specifically mentioned, there could be less or more groups.The generally C-shaped seat rails of a group could come in differentmoldings; that is, the C-shaped moldings could have different sizes orcould have different shapes with respect to the partially encompassing.This can be achieved by producing the seat rails of one group withdifferent molding sizes in the same machinery from metallic (e.g.,steel) sheet strips of differing width.

Further regarding the possibility of modularly constructing thelongitudinal adjuster of the present invention, it is also possible forit to be manually driven or driven by a motor.

Because of its modular construction, such as with regard to spindles andseat rails, the longitudinal adjuster of the present can be used forvarious purposes. The sides of the seat rail assemblies can berespectively mounted, such as by bolting, to the vehicle structure andthe vehicle seat elements, and they can alternatively be mounted byother means, such as by welding.

Other aspects and advantages of the present invention will becomeapparent from the following.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is explained in greater detail below withreference to one exemplary embodiment illustrated in the drawings, inwhich:

FIG. 1 shows a cross section through the embodiment, and this drawing ispartially schematic, for example in that the round spindles and/or roundpassageways through the spindle nuts are schematically illustrated asnon-circular,

FIG. 2 schematically illustrates a vehicle seat, and

FIG. 3 shows various seat rails in different molding sizes.

DETAILED DESCRIPTION OF THE INVENTION

Referring now in greater detail to the drawings, in which like numeralsrefer to like parts throughout the several views, a vehicle seat 1, inparticular a motor vehicle seat, includes a longitudinal adjuster 3 forthe purpose of adjusting the longitudinal seat position. Thislongitudinal adjuster has a seat rail assembly 5 on both sides of thevehicle seat 1. Each seat rail assembly 5 is connected to the vehiclestructure, on the one hand, and connected the seat element 7 of thevehicle seat 1, on the other hand.

Each seat rail assembly 5 includes three molded, elongate seat rails. Afirst seat rail 11 a is located on the inside, a second seat rail 12extends partially around the first seat rail, and a third seat rail 13 bextends partially around the second seat rail. This arrangement outlinesan installation space 15 which is encircled by the combination of theseat rails 11 a, 12, and 13 b. The first seat rail 11 a and the thirdseat rail 13 b are fixedly connected to one another. The first and thirdseat rails 11 a, 13 b are together movable in the common longitudinalseat rail direction relative to the second seat rail 12. In order toreduce friction, balls 17 are located between the second seat rail 12and the third seat rail 13 b. The side of the second seat rail 12 isconnected to structure of the vehicle. The sides of the first and thirdseat rails 11 a, 13 b are connected to the seat element 7.

Depending on the load requirements, in particular with regard toresisting detachment such as between components of the seat railassembly 5, the seat rail assembly 5 can be modularly constructed. Forexample, a relatively more completely molded first seat rail 11 b (FIG.3) can be used in place of the relatively less completely molded firstseat rail 11 a, and/or a relatively less completely molded seat rail 13a (FIG. 3) could be used in place of the relatively more completelymolded third seat rail 13 b. The first seat rails 11 a and 11 b can becharacterized as forming a group, and the third seat rails 13 a and 13 bcan be characterized as forming another group. The seat rails of onegroup can be produced in the same machinery from steel sheet strips ofdifferent widths. It is also possible to cut them into appropriate sizesafter they are produced by the machinery. The desired adjustment (e.g.,modularity) could also be achieved by leaving out the first seat rail 11a/ 11 b or the third seat rail 13 a/ 13 b. A further adjustment could beachieved by placing different amounts and arrangements of balls 17between the three possible seat rails.

In order to drive the longitudinal adjuster 3 by way of a motorizeddrive, each of seat rail assemblies 5, which are respectively locatedproximate the sides of the vehicle seat 1, includes a first spindle 20inside of the installation space 15 and extending in the longitudinalseat rail direction. For each of the seat rail assemblies 5, both endsof its spindle 20 are fixedly connected to the second seat rail 12.Internally threaded, first rotatable spindle nuts 21 are respectivelyplaced on each of the first spindles 20, so that the internal threads ofthe first spindle nuts respectively mesh with the external threads ofthe first spindles. As a result, each first spindle nut 21 can rotatablytravel along the respective first spindle 20 and thereby cause theassociated second seat rail 12 to travel relative to the associatedfirst and third seat rails 11 a, 13 b. More specifically in accordancewith the exemplary embodiment, while each first spindle nut 21 rotatesaround its respective first spindle 20, travel of the first spindle nut21 in the longitudinal direction relative to the first and third seatrails 11 a, 13 b is restricted in a conventional manner, so that theassociated first spindle 20 and second seat rail 12 travel together inthe longitudinal direction relative to the first and third sear rails.

For each of the seat rail assemblies 5, external teeth of the firstspindle nut 21 (e.g., worm gear) mesh into external threads of a worm23. The worm 23 is mounted in a conventional manner so that movement ofit in the longitudinal direction relative to the first and third seatrails 11 a, 13 b is restricted. In accordance with the exemplaryembodiment, each worm 23 is turned by a respective shaft 25, and theseshafts are powered by a common motor 27. That is, a single motor 27 cansubstantially simultaneously turn the worm 23 of each seat rail assembly5.

The installation space 15 is dimensioned in a way that allows room for asecond spindle 30 and a second spindle nut 31. For example and not forthe purpose of narrowing the scope of the present invention, the secondspindle 30 and the second spindle nut 31 may be desired (e.g., required)in the installation space 15 proximate the side of the vehicle seat 1 towhich the seat belt buckle (not shown) is mounted. For example, for thepair of seat rail assemblies 5 illustrated in FIG. 1, the seat beltbuckle assembly can be connected to the side of the seat 1 that includesthe seat rail assembly 5 with the two spindles 20, 30 and the twospindle nuts 21, 31, as opposed to being connected on the side of theseat that includes the seat rail assembly with only one spindle 20 andone spindle nut 21.

In accordance with the exemplary embodiment, this second spindle 30would be positioned parallel to the first spindle 20 and is also fixedlyconnected to the second seat rail 12, and the second spindle 30 isthreaded in the opposite direction as compared to the first spindle 20.Internal threads of a second spindle nut 31 mesh with the externalthreads of the second spindle 30 so that the second spindle nut 31 canrotatably travel along the second spindle 30. More specifically inaccordance with the exemplary embodiment, while the second spindle nut31 rotates around the second spindle 30, travel of the second spindlenut 31 in the longitudinal direction relative to the first and thirdseat rails 11 a, 13 b is restricted in a conventional manner, and thesecond spindle 30 and second seat rail 12 travel together in thelongitudinal direction relative to the first and third sear rails.

In accordance with the exemplary embodiment, external teeth of thesecond spindle nut 31 (e.g., worm gear) mesh with the external threadsof the previously mentioned worm 23, so that the common worm 23 providesa substantially synchronous drive for both spindle nuts 21 and 31.

Clearance is provided between the second spindle nut 31, on the onehand, and the second spindle 30 or the worm 23, on the other hand, inorder to avoid blocking (e.g., jamming of) the motor 27, in accordancewith the exemplary embodiment of the present invention. In accordancewith the exemplary embodiment, the system of the first spindle 20 servesthe purpose of longitudinal adjustment, whereas the system of the secondspindle 30 serves the purpose of increasing the longitudinal lockingforce. In order to adjust the longitudinal locking force, the seat railassemblies 5 can be modularly provided with one or two spindles, each incombination with a modular assembly of the seat rails. It will beunderstood by those skilled in the art that while the present inventionhas been discussed above with reference to exemplary embodiment(s),various additions, modifications and changes can be made thereto withoutdeparting from the spirit and scope of the invention as set forth in thefollowing claims.

1. A longitudinal adjuster for a vehicle seat, the longitudinal adjustercomprising: at least one seat rail assembly including (a) elongate seatrails that are shaped and mounted together (1) for there being relativelongitudinal movement therebetween, and (2) so that the seat railscooperate with one another to define an installation space, and (b) atleast a first spindle nut and at least a first spindle that are withinthe installation space and mounted (1) so that the first spindle nut andthe first spindle are meshed with one another, and (2) for there beingrelative rotation between the first spindle nut and the first spindle,with the relative rotation causing at least the relative longitudinalmovement between the seat rails, and wherein the installation space isconfigured in a predetermined manner to be capable of having a secondspindle nut and a second spindle meshed together and within theinstallation space.
 2. The longitudinal adjuster according to claim 1,wherein the second spindle nut and the second spindle are within theinstallation space and mounted (a) so that the second spindle nut andthe second spindle are meshed with one another, and (b) for there beingrelative rotation between the first spindle nut and the first spindle,with the relative rotation between the second spindle nut and the secondspindle being restricted so as to be at least substantially simultaneouswith both (1) the relative rotation between the second spindle nut andthe second spindle, and (2) the relative longitudinal movement betweenthe seat rails.
 3. The longitudinal adjuster according to claim 2,wherein the second spindle extends parallel to the first spindle, andthe first spindle and the second spindle are threaded in oppositedirections with respect to one another.
 4. The longitudinal adjusteraccording to claim 1, further comprising a worm mounted (a) so that theworm is meshed with the first spindle nut, and (b) for rotating andthereby causing at least the relative rotation between the first spindlenut and the first spindle.
 5. The longitudinal adjuster according toclaim 2, wherein: the longitudinal adjuster further comprises a wormmounted (a) so that the worm is simultaneously meshed with each of thefirst spindle nut and the second spindle nut, and (b) for rotating andthereby causing at least the relative rotation between the first spindlenut and the first spindle; and wherein clearance is provided between thesecond spindle nut and one or more of the worm and the second spindle.6. The longitudinal adjuster according to claim 4, wherein the seat railassembly is a first seat rail assembly, and the longitudinal adjusterfurther includes (a) a second seat rail assembly including a worm for atleast partially driving relative longitudinal movement between elongateseat rails of the second seat rail assembly; and (b) a drive connectedby at least one shaft to both the worm of the first seat rail assemblyand the worm of the second seat rail assembly for simultaneously (1)turning the worm of the first seat rail assembly so that the worm of thefirst seat rail assembly drives at least the first spindle nut to causeat least the relative rotation between the first spindle nut and thefirst spindle, and (2) turning the worm of the second seat rail assemblyso that the worm of the second seat rail assembly at least partiallydrives the relative longitudinal movement between the seat rails of thesecond seat rail assembly.
 7. The longitudinal adjuster according toclaim 1, wherein the seat rails includes at least three seat rails thattogether are a modularly constructed unit, with the seat rails beingselected from at least three groups of seat rails.
 8. The longitudinaladjuster according to claim 7, wherein at least a first group of thegroups of seat rails includes seat rails shaped differently with respectto one another.
 9. The longitudinal adjuster according to claim 8,wherein the seat rails of the first group that are shaped differentlywith respect to one another were produced in the same machinery fromsteel sheet strips of differing width.
 10. The longitudinal adjusteraccording to claim 1 in combination with the vehicle seat, so that thevehicle seat is longitudinally adjustable by way of the longitudinaladjuster.
 11. The longitudinal adjuster according to claim 2, furthercomprising a worm mounted (a) so that the worm is simultaneously meshedwith each of the first spindle nut and the second spindle nut, and (b)for rotating and thereby causing at least the relative rotation betweenthe first spindle nut and the first spindle.
 12. The longitudinaladjuster according to claim 3, further comprising a worm mounted (a) sothat the worm is simultaneously meshed with each of the first spindlenut and the second spindle nut, and (b) for rotating and thereby causingat least the relative rotation between the first spindle nut and thefirst spindle.
 13. The longitudinal adjuster according to claim 12,wherein clearance is provided between the second spindle nut and one ormore of the worm and the second spindle.
 14. The longitudinal adjusteraccording to claim 5, wherein the seat rail assembly is a first seatrail assembly, and the longitudinal adjuster further includes (a) asecond seat rail assembly including a worm for at least partiallydriving relative longitudinal movement between elongate seat rails ofthe second seat rail assembly; and (b) a drive connected by at least oneshaft to both the worm of the first seat rail assembly and the worm ofthe second seat rail assembly for simultaneously (1) turning the worm ofthe first seat rail assembly so that the worm of the first seat railassembly drives at least the first spindle nut to cause at least therelative rotation between the first spindle nut and the first spindle,and (2) turning the worm of the second seat rail assembly so that theworm of the second seat rail assembly at least partially drives therelative longitudinal movement between the seat rails of the second seatrail assembly.
 15. A longitudinal adjuster for a vehicle seat, thelongitudinal adjuster comprising: elongate seat rails mounted togetherfor there being relative longitudinal movement therebetween; at least afirst spindle nut and at least a first spindle that are mounted (a) sothat the first spindle nut and the first spindle are meshed with oneanother, and (b) for there being relative rotation between the firstspindle nut and the first spindle, with the relative rotation causing atleast the relative longitudinal movement between the seat rails; atleast a second spindle nut and at least a second spindle that aremounted (a) so that the second spindle nut and the second spindle aremeshed with one another, and (b) for there being relative rotationbetween the second spindle nut and the second spindle, with the relativerotation between the second spindle nut and the second spindle beingrestricted so as to be at least substantially simultaneous with both (1)the relative rotation between the first spindle nut and the firstspindle, and (2) the relative longitudinal movement between the seatrails; and a worm mounted (a) so that the worm is simultaneously meshedwith each of the first spindle nut and the second spindle nut, and (b)for rotating and thereby causing at least the relative rotation betweenthe first spindle nut and the first spindle.
 16. The longitudinaladjuster according to claim 15, wherein: the second spindle extendsparallel to the first spindle, and the first spindle and the secondspindle are threaded in opposite directions with respect to one another,and clearance is provided between the worm and the second spindle nut.17. The longitudinal adjuster according to claim 15, wherein the seatrails cooperate with one another to define an installation space, andwherein at least the first spindle nut, the first spindle, the secondspindle nut and the second spindle are within the installation space.18. A method for providing a modular seat rail assembly for alongitudinal adjuster for a vehicle seat, the method comprising: (a)selecting seat rails from a plurality of groups of seat rails, wherein(1) the groups of seat rails includes at least a first group of seatrails, a second group of seat rails, and a third group of seat rails,(2) the seat rails of the first group of seat rails are shapeddifferently from both the seat rails of the second group of seat railsand the seat rails of the third group of seat rails, (3) the seat railsof the second group of seat rails are shaped differently from the seatrails of the third group of seat rails, (4) at least one of the selectedseat rails is from the first group of seat rails, and (5) at least oneof the selected seat rails is from the second group of seat rails; (b)assembling the seat rail assembly, with the assembling of the seat railassembly including mounting the selected seat rails together so thatthere can be relative longitudinal movement therebetween, and mountingat least a first spindle nut and at least a first spindle so that thefirst spindle nut and the first spindle are meshed with one another andthere can be relative rotation between the first spindle nut and thefirst spindle, with the relative rotation causing at least the relativelongitudinal movement between the selected seat rail and the first seatrail which are mounted together.
 19. The method of claim 18, wherein atleast the first group of seat rails includes seat rails shapeddifferently with respect to one another.
 20. The method of claim 19,further comprising producing the seat rails of the first group that areshaped differently from one another in the same machinery respectivelyfrom thin, steel strips of differing widths.